Pneumatic socket for artificial limbs



July 19, 1932. L. w. BALcH ET Al.

PNEUMATIC SOCKET FOR ARTIFICIAL LIMBS Filed sept. 1 9, 41929 f Y I Patented July 19, 1932 Y l LUXE-,WQBALGHAND EDWARD'DE WAGENAERE, oFM'INNEAroLs, MINNESOTA PNEUMAmIcYsocxET FoalieTiricIAnmnns-L This invention relatesltowartifci'al limbs and especially tothe socketlconstruction thereof, whichl is adapted to receive and form n the bearingfor rthe" stump of the'limb.

f It is an object 'of our invention toprovide an e'flicient pneumatic socket structure for artificial limbs, which will supplythe maximum amount of eomfort to' the wearer, which Y Williefectively cushionuthe stump, making T9 special provision for the prominent bones thereof, and which is adjustable by inflation to'compensatefor the shrinkage of the stump and to meet different `requirements on the part' of the wearer;V n

1:5 A further object of our invention is 'to provide'in'art'ifieial `limb structure, a pneumatic socket for eiciently `fitting and cushioning the stump, wherein anfi'nflatable'bag or'bearing 29 with the socket shell that itscushioning effect will be exerted scientifically over' 'a large area ofthe stump.V 1' y l f We, of course,V realizerthat we' are not the first to utilize an inflatable bag in `Vthe=socket J structure of artificial.limb`s,but 'in all .pneu

matic; socket constructions known to. usat this time the inflatable bags, which are usu ally annular, are .so .related and combined y with the shell ofthe socket that they swell or 30 bulge, when inflated, inwardly.approaching in cross section'a semi-circle and thereby fen`` circling only a relatively small areaofthestump. Such inflatable socket structures choke the blood circulation ,in the' stump'and 35 usually 'must beideflated beforethewarticial limbmay be removed from the wearer. lThe continued usageof d'evicesof this 4type has proven harmful tofthe' amputated limb.`

It`is,therefore, a further object of 'our in-y 40 vention to provide pneumatic socket structure employing a pne'umaticpad which is so con-I nected and related with th'ezshellofthev socket that it wil-l engageV the entire bearing area ro f the stu-mp, thereby obviating the objec-v` 40 'tionable' features enumerated in ,the preceding paragraph Y ,'Anothefr object of ou'rinvention is to provide pneumatiosocket structure `for artificial i limbs Whereina somewhat `greater amount Si of `pneumatic cushioning is suppliedzfor the limb for a limb amputated below lthe knee pad is so connected and relatedl ving ormingmaterial being broken" Aaway-f;

prominent bones ofthe `stumpV than ref mainder ofithefareaof the stump engaged.

' Still-fanotherobjectis to providevaynew l I the invention- `will dbe fully set forth'in thev V following descriptionlwmade in `connection' G0 with-the accompanying drawing' wherein like reference characters .refer to` similar' parts Y throughout-the several viewsand in which, Fig. 1 is a perspective vew'of'an artificial having Van `'embodiment Vof ourVv invention i therein, Fig.- 2 isa-vertical sectionv taken? through t thefstump portion of the artificia'll limb'shown 'i in Figll l V i i Fig. 3 is across section of our improved socket structure. detached, taken onthe line 3"-13of Fi'gz2; Y- V:` i ig; 4 ifs aplan view of our inflatable bag i detached and laid'out flat; y

w75' Figo is a erosstsecti'on takenon` the line i, 545,0Fig94y1` Y y Fig'. 6 israln enla-'r' edfdetail i cross section valvel construction; y Y Y v K Figf afperspectiye View of a castmodel of a stumpfv illustrating several steps "in our novel.'` 'method f' `for making? `the pneumatic Y socket strueturejsome"portions of the '.bear-4 taken onthe'line of FigiY 2,1showingfour Fig.V 8 is a perspective' view of lthe stump` model illustrating someof the' other steps in ourxmethodl n fi In' Fig. 1 of the'drawing, anartifeiallimb for afbelow-the-lme'e 'amputationl is -s hown` havingfthje usual shank or casing S,and the corset or lacing portion- L, said portonsbe-l ing 'swivel/lyconnectedat the "knee of the wearerv vby: thel usual l'meewp'ivot's P fAThe" shankfSI usually includesanjinner woo'denf Y f case' ac'o'vered `with a' layer o'traw` hide l5",

the raw hide extending upwardly beyond-the upperfedgebf case a to receive the socket stmicture.l i Thez'upper edge' of ,case "af con stitutes'ian abutment tof support ythe lower 'edge ofthe sock-'et shell. To: the 'lower end 'ofshank S,the usual ankle V'portion A is swivellyattachedhaving the toe portion T of the limb jointed'thereto. f l' f Our invention resides in the provision of a Apneumatic socket structure at tle vstump opening ofV theshank S. We provide a socket shell '10, preferablyrconstructed of leatherY or some other suitable'material having some The shell 10 is annular and stump@` Y Shell 10 .is so-,constructed that the portions thereof wherein the prominent bones; of the 'f stump aredisposed Will b'e'bulg-ed outwardlyV slightly. beyond the `actu'al'contour; of said bones. We.. refer to the tibia, `andifib'ula' bones of the leg andthe lower vend .offthe femur bone of thethigh. :In Fig." 3 the` tibia i receiving bulge of the socket shell isindicated kby the numeral 10a, the ibula-receiving bulge,

by the numeral 10b, and the.y femur receiving bulge by thenumeral 100.3 Shell'lO isusually I'const-ructedfrom a single strip of material,l

the end edgesv being'ta'pered in cross section and stitched'or Votherwise secured together at the calf portionoftheshell. l f2 l XVe-provide aspecial inflatable padQWh-ich Y is cemented or adhesively secured to theinner I surface of the socket shelllO, Our pad coin- J l prises anouter: sheet 11 of rubberized fabric shell 10` and covers the interior'of the beg,-

or other suitable material, Which is: relatively non-elastic and i an -inner sheet512, of thin Y elasticiV material, `su'chifaspure-gum rubber.

Both sheets k11 and 12 at their upper .edges arerv cutA along a curved line', which is -deter-` ymined accurately fromithe plaster model of j thestump,tlater.to-be described. The upperA e edges are'sov curved that theywill properly engage the upper portion of fthe stump to'v insure."comfortjThe upper ledge of the elastic sheet-12 isifolded abouttheupper edgef of sheet zllfa'nd-vulcanized or l:otherwise selower land side edges ;may. coincide Withrthe,

edges ofi-.sheet 12l and are or secured-thereto'.4

We provide an eiiicient lvalve structure by which 'our bag-maybe,inflatedbrdelated, although,ofcourse, other's'uitable valvesmay H be employed. As shown, our inflationvalve comprises a tubular' stemY 13, lexternally Y threaded at its :outer portion Y' `andr having rigidlyr..attached to thei'nner end thereovvav bridge-Washer 13a, Which isadapted to en-A gagethe-inner surface of fabricsheet 11. The innerportion of'. sleeve 1 3 Hhas a Vdimin-V *ished' airport 13?) outwardly offivvhich'fis disposed a concave'valve'seat 14, which may suitably vulcanized Y ing an axial bore 15avterminating atits inner endfin a yradially extending outlet,vvhich is adaptedfto communicate with the port 13bV When member 15 is loosened. Theinner en d' of member v15is externally threaded to engage internal threads on valve stem V13 and the outer end ofl member 15 is provided With ari/enlarged head.y 15?),.vvhich Vis internally threaded to receive the discharge end 'of a suitable pump. 'A strip of elastic materiall, such 'as rubber,is stretched across the 'flat' winner, surface 'ofjbridge Washer 13a normally closing theport '1312V Stef "13 is yadapted to project through an aperture 10d, formed in the inner Yside of shell VlOfor convenient Y,inlation bygthewearerggf t f .A

1 The entire,l outer.A surface 'ofV :Eabricsh'eet 11 of ourinliatable bagfisv adhe'sively. secured byrubber, cement or other suitable ,material to' theinnersurface ofhsocket'shell 10,' and shell.- The ends of thebag are spaced'slightl-y i" apartacross the calf portion ofthe shell, as.

'clearly shown in F ig. 3, andidue to Athe manf ner in Whi ch the side or'end edgesof the sheets V I is 'positioned at allpointssmoothly against Y 11V and 12 are joined, Whenthe bagisinated, Y

taper nicely in cross section t0 conform-tothe l Y liner 17, constructed of some. y soft ilexiblematerial, such as elk hide, is old-y calf. v ,A suitable ed at its upper Iedge` about lthe upper .edge

or4 thev bag vandthe adjacent upper edge of. l

having av .depending :skirt Whichl usually exs tends below the socket. VThe linerv 17 isfprefer'ably made fromfa single sheet of material Withthe end edgeS overlappingfat thevcalf Portion of theartificial.limb.-V Y f Y l' InlA constructing our' improved v 'pneumatic plasterV castingfar'e then f partially l,covered With' suitablyV formed pie'ceswof V'leather Y orA othermaterial to slightly exaggerate` the n contour of the prominentbones ofthe stump. j

andV thesepieces may be'tac'ked orV otherwise secured to casting f Suitable-material, such f as heavy leather isthen soaked in .water until Y it is properly saturatedtonrender it'iiexible and to` some extent 'stretcha'ble 1 The soalied material is Ythen tightly stretchedV abouti the prepared casting andsecured thereto to form Usually,fthe covering Z`,'is securedy byfamuL.

pared casting.' 'l`hisfcovering,withthe p re-v Y f pared-casting, iorms'the 'actual' model'for the shell '10 ofourfsoclet; The leather'vcovering Z isof such -thicknessas to properly compen` sate fOr tliegthiclrness'of kthe 'materialft'rom which the inflatable pad is made as well as the leather lining 17.

Another sheet of leather or other suitable material is` soaked in water and tightly stretched about the described model, and is tacked to the model as shown in Fig. 8, its overlapping edges being tapered to afford a smooth joint. When the leather for shell is dry, it will be almost a perfect replica of the model from which it is made and will have suicient rigidity to retainits shape although having some flexibility and resiliency.

Our inflatable pad is cemented to the inner surface of shell 10 in the manner previously described and the leather liner 17 is stitched or otherwise secured to the upper edge of sh ell l0 completing the socket structure.

Due to the exaggerated outwardly bulged portions of the shell 10, wherein the tibia, fibula and lower end of the femurbones are disposed, a slightly greater cushioning effect, as clearly shown in Fig. 3 will be present at those sensitive portions. That is: the air cushion between the sheets 11 and 12 ofthe pad at the bone receiving portions -of ,the

socket will be greater in thickness than the air cushion at the other portions of the socket. When inflated, the elastic wall 12 offthebag will be distended substantially parallel lwith the cemented non-elastic wall11,thereby caus ing practically the entire area of the stump to be engaged and cushioned. The bag will not bulge inwardly and circumferentially at its mean height in the manner of inflatable bags utilized at this time. Only a small amount of air is inserted inthe bag. lt will be noticed that due to the construction of the bag at'its upper edge the air cushion. formed extends to the extreme upper edge of the socket shell 10, thereby preventing the edges of the shell from cutting or chafing the stump.

In Figs. 1 and 2, the position of the stump in the artificial limb is indicated in dotted lines. When the weight of the body is thrown upon our pneumatic socket, it will be obvious that the prominent bones and sensitive portions will be adequately cushioned by the bag in combination with the slightly exaggerated outwardly bulged portions of the'socket shell. The upper and lower edges of the bag cannot draw or creep, since the entire surface of the i non-elastic fabric 11 is cemented to the shell, and in actual practice we have found 1li-at a greater degree of comfort will be obtained Y from our socket structure than with any other construction known-to us at this time.

From the foregoing description it will beVV apparent thatV we have provided a novel, comparatively simple and highly efficient socket Astructure for artificial limbs adapt-ed for the wearer is walking a considerable distance where excess of cushioning is needed, the increased body heat of the stump increases slightly theair pressure in the bag, providing the increased cushioning effect. `The lower portion of the stump can never be choked by our .socketV structure. The artificial limb, when inflated, maybe readily applied or removed without varying the contents of air in the bag. p

It will, of course,.be understood that various changes may bemade in the form, details, arrangement and proportions of the parts without departing from the scope-of applicants invention. l

What is claimed'is l:v

l. In artificial limb construction, a pneuf ioning bag extending at least partially around the interior of said casing, said bag comprising inner and outer parallel plies of material, the Vouter ply being constructed of relatively thick stiffened non-elastic material and the inner ply being constructed of relatively thin elastic material, the outer surface ofthe outer ply being adhesively secured tothe inner surface of said casing to prevent drawv Y vIn testimony whereof we` aflix our signa@ tures.

LUKE W. BALCH. v EDWARD DE WAGENAERE. 

